Summary The concept of sarcopenia as a clinical biomarker to identify older adults at risk of physical disability and poor health outcomes, based on the measurement of lean soft tissue mass, muscle strength, or other measures of physical function, has considerable appeal to older adults at risk for physical disability, the practicing clinicians, and to the pharmaceutical companies, that are engaged in the development of function promoting therapies. The lack of consensus on how to diagnose sarcopenia has limited the ability of practicing clinicians to diagnose this condition and hindered drug development efforts. The Sarcopenia Definition and Outcomes Consortium (SDOC, the Consortium) was formed to address this global public health need. In 2016, the National Institute on Aging (NIA) and the Foundation for the National Institutes of Health (FNIH) funded the Consortium to develop evidence-based cutpoints for lean body mass and muscle strength to identify persons at risk for mobility disability and other adverse health outcomes, such as falls, IADL disability, and death. The initial findings of the analyses were presented at a meeting in Bethesda, MD, in October 2017 that included members of the Consortium, additional experts from around the world, and the NIA and FNIH program staff. The outside experts and NIH and FNIH staff made several recommendations to facilitate the translation of the Consortium's findings into an evidence-based definition of sarcopenia, including the formation of an International Expert Panel to work cooperatively and iteratively with the SDOC to review the analytical results and published evidence, and a series of Position Statements leading up to a conference to facilitate the development of a consensus on how to define sarcopenia. This conference grants seeks NIH support for such a Position Development Conference for Sarcopenia Definitions and Outcomes. Accordingly, we have established an International Expert Panel which includes content experts from around the world, representatives of professional societies, regulatory agencies, pharmaceutical companies, patient advocacy groups, and other stakeholders. The International Expert Panel will review the findings of the SDOC's analyses and the published information, and review a set of Position Statements on sarcopenia definition presented to it by SDOC in monthly conference calls in early and mid-2018. These Position Statements, refined as a result of an iterative interactions between the SDOC and the International Expert Panel, will be presented, discussed, and voted on at the Position Development Conference on November 13, 2018 in Boston, MA. The Conference will be held just prior to the annual meeting of the Gerontology Society of America. The deliverable of the Position Development Conference will be a set of evidence-based position statements on the definition of sarcopenia guided by the results of the proposed analyses and synthesis of the published literature and approved by the International Expert Panel, and published in high quality peer- reviewed journal/s.